The state of the art booster rocket engines are designed to utilize solid or liquid propellants, individually, as a bipropellant or in combination as a tripropellant, where the fuel has been O.sub.2, H.sub.2, and/or HC. Historically, tripropellant liquid rocket engines have utilized H.sub.2 to cool the thrust chamber and burn in the gas generator but theretofore the H.sub.2 has never been used or considered for use in the main combustion chamber. Other than the space shuttle main engine which uses O.sub.2 and H.sub.2 which operates at 3000 psi in the combustion chamber (PC), booster rocket engines such as the Saturn, Delta, Atlas, etc. are known to operate at relatively low PC, say between 700-1200 psi and the liquid O.sub.2 and H.sub.2 rocket engines such as RL10 and J-2 operate at lower ranges of PC (400-700 psi). For future space missions, particularly of the low earth orbit type, there will be a need for a class of booster rocket engines that will require reusable rocket engines, be capable of propelling large payloads, be launched frequently and will be within limited cost constraints and afford operational flexibility.
As is well known, the engines of the future will have to operate at the high PC such that attainable by the SSME and still provide the capabilities enumerated above. To this end such an engine will require a high density, high energy fuel that will provide the necessary mass flow to produce the thrust capabilities necessary for launching significant payloads into low earth orbit. Liquid HC fuels are known to possess such characteristics. Notwithstanding that which is understood about the advantages afforded by HC fuels, it is also well known that liquid HC exhibits certain characteristics that inhibit their use and these are namely:
(1) combustion instability PA1 (2) low combustor efficiency PA1 (3) poor cooling capabilities PA1 (4) delayed ignition, and PA1 (5) carbon/soot in the combustion products.
This invention contemplates the use of hydrogen injected into the combustion chamber of the rocket engine in a judicious manner in order to provide the atomization and mixing of the hydrocarbons and oxygen fuels. Such a system affords an improvement in engine performance and ignition while minimizing or completely eliminating combustion instability.